Caesarean babies lose gut bacteria and risk developing asthma
12th February 2013
Babies who are delivered via a caesarean section may be exposed to numerous dangers such as a surgical injury (accidental nicks to the baby's skin during surgery). There are also risk of potential breathing problems to the baby like transient tachypnea—abnormally rapid breathing during the first few days after birth and respiratory distress syndrome — a condition that makes it difficult for the baby to breathe. And now a new study recently published in the Canadian Medical Association Journal has identified that babies born in this particular manner could have fewer than normal ‘good’ bacteria in their digestive tract and thus not benefiting from these protective bugs preventing health problems in childhood and later life such as asthma and allergies. Researchers in Edmonton, Winnipeg, Toronto and Hamilton claim that they have compiled evidence that demonstrates infants born by caesarean delivery actually lack group of bacteria common in the stool of those infants delivered naturally, regardless of being breastfed or not. In particularly, babies born by c-section had significantly fewer bacteria of the Escherichia-Shigella and absolute nothing of the Bacteroides species. “Shigella and Bacteroides are organisms picked up from mom and considered first colonizers,” says senior author Anita Kozyrskyj. “They lay the foundation for further microbes that become part of our normal microbiome.” For the study, examinations were carried out on the stool samples from 24 healthy infants who are part of the larger Canadian Healthy Infant Longitudinal Development (CHILD) study. Samples were obtained as the babies reached four months of age. The comprehensive microbial survey was feasible because of advances in DNA sequencing techniques. The researchers state that the potential long-term consequences of decisions in relation to the way in which a baby is delivered and an infant’s diet are ‘not to be underestimated’. In their report, the researchers comment: “Infants born by caesarean delivery are at increased risk of asthma, obesity and Type 1 diabetes, whereas breastfeeding is variably protective against these and other disorders. Our findings are particularly timely given the recent affirmation of the gut microbiota as a ‘super organ’ with diverse roles in health and disease, and the increasing concern over rising caesarean delivery and insufficient exclusive breastfeeding in Canada.” Specific reasons for the differences in gut bacteria have not been fully established, but it could be that caesarean-born babies are missing out on physiological changes occurring during labour that includes exposure to bugs that are necessary for the immune system to develop. Interestingly, in Canada where the study was primarily focused on, a parallel rise of caesareans and certain illnesses such as asthma has been witness in the last two decades.  In 1990, roughly 18% of all births were delivered by this method and statistics now show that c-sections currently comprise of about 27% of all births within Canada. The prevalence of asthma has also increased during this time period and there are now about three million Canadians who suffer with the lung condition. This is in addition to the 5.4 million Brits currently receiving treatment for asthma and many more millions worldwide. Rob Knight, associate professor at the University of Colorado and a co-author of a commentary published with the study, said: “C-section and asthma could be connected. There have been several studies showing that more diverse microbial communities lead to lower rates of asthma, allergies and autoimmune diseases, and this study shows that c-section leads to lower microbial diversity.”